Mechanical circulatory support devices have become increasingly common in the treatment of end stage heart failure, primarily in the form of the Left Ventricular Assist Device (LVAD). Survival and quality of life have improved steadily, due to the transition from larger pulsatile devices to small continuous flow devices, as well as improved patient selection and management. The most significant impediment to broader adoption of this technology, especially in less sick and more active patients, is the rate of infection. Current VADs require a percutaneous cable, which must be carefully managed, and which prevents patients from activities that put physical stress on the exit wound or that expose the site to water. The long term objective of this project is to develop and market TETS technology for wireless power and data transmission for use in continuous flow LVADs. Our goals are: 1) to achieve reliability and durability necessary for long term (10 year) use in patients, 2) to design implantable and external coils which can be implanted with minimal surgical trauma, result in no significant tissue inflammation due to coil materials or heat generation, and take into consideration patient quality of life and usage patterns, and 3) to promote adoption of the TETS technology by LVAD manufacturers by reducing their time and cost for implantable system development, and providing test data and documentation required for regulatory approval. The Phase II specific aims are to: 1) optimize the coil design, 2) develop TETS electronic hardware and software, using scalable system architecture, 3) incorporate wireless communication, 4) perform in vitro characterization testing, and 5) assess biocompatibility and tissue temperature through in vivo studies.